A system for indoor cultivation of plants with simulated natural lighting conditions

ABSTRACT

An indoor soilless plant cultivating system. The system has a plurality of (a) stationary light posts, (b) plant growth towers, and (c) irrigation means. Each post is adapted to illuminate a predetermined sector of an indoor facility in accordance with a predetermined illumination signature. Each tower is rotatable about a substantially vertical axis in accordance with a predetermined timing sequence so as to be exposable to the light generated at any given time by one or more of the light posts and that are arranged by at least one module defining a module darkened interior region within which plants being instantaneously positioned receive a sensation of nighttime. The irrigation means supplies the plants being cultivated in each of said towers with a nutrient-rich solution.

This application is a continuation-in-part application of U.S. patentapplication Ser. No. 15/557,194, which is a national phase applicationof international patent application no. IL2016/050300 filed on Mar. 18,2016, which claims priority from U.S. patent application No. 62/135,514filed on Mar. 19, 2015.

FIELD OF THE INVENTION

The present invention relates to the field of a plant cultivatingsystem. More particularly, the invention relates to an indoor soillessplant cultivation system, for cultivating plants in a nutrient-richsolution.

BACKGROUND OF THE INVENTION

Many people are attracted to living in urban settings by virtue of theeconomic progress that may be realized. Cities bring together diversegroups of people and companies in ways that increase productivity andcreate the networks, clusters, and chance interactions that lead to thediscovery of new innovations and the creations of new entrepreneurialbusinesses. Other advantages of living in urban settings include thelarge number of cultural activities that are available and the relativeease in commuting to work.

While 60% of the human population now lives in cities and are protectedagainst the outdoor elements, food-bearing plants are subjected to therigors of the outdoors. People hope for a good weather year in order toensure that the food supply will be readily available. Many times due toa rapidly changing climate regime, however, massive floods, protracteddroughts, class 4-5 hurricanes, and severe monsoons take their toll eachyear, destroying millions of tons of valuable crops.

By the year 2050, nearly 80% of the earth's population will reside inurban centers. Applying the most conservative estimates to currentdemographic trends, the Earth's population will increase by about 3billion people during this period. An estimated 10.9 million square kmof new land (about 20% more land than all of Brazil) will be needed togrow enough food to feed them, if traditional farming practices continueas today. At present, throughout the world, over 80% of the land that issuitable for raising crops is in use. Historically, some 15% of thatagriculturally suitable land has been laid waste by poor managementpractices. Indeed, much land has become despoiled, such that naturaleco-zones have been converted into semi-arid deserts.

The traditional agricultural practice of growing food-bearing plantsoutdoors, or within greenhouses located at agricultural areas, isproblematic in terms of weather related or pest related crop failure,the cost of transporting the grown crops to food distribution centers,the ecological damage due to fossil fuel emissions from the vehiclesthat transport the crops and that are used for performing agriculturalactivities such as plowing, the cost for fertilizers and pesticides, theoccurrence of infectious diseases acquired at an agricultural interface,and ecological damage due to agricultural runoff.

In order to sustain the Earth's growing population, it would bedesirable to learn how to safely grow food within city-located,environmentally controlled multistory facilities, in order to maintain areadily available food supply while overcoming the problems associatedwith traditional agricultural practices.

Some indoor hydroponic system are known from the prior art wherein plantgrowth units are stacked one on top of another, a solution of water andplant nutrient is introduced to the plants, and panels comprisingartificial light sources that eliminate the need for natural sunlightand enable light cycles of varied duration are provided on top of eachplant growth unit.

Photoperiodic flowering plants flower in response to a sensed change innight length, and therefore require a continuous period of darknessbefore floral development can begin. However, the prior art light panelsfor simulating such light cycles are costly due to the need of a lightpanel at each level of a growth unit and of a dedicated control systemfor each panel. Additionally, the light panels are self-heating, andexpensive to operate cooling systems are needed to remove the generatedheat.

Light-emitting diodes (LEDs) have been found to be ideal light sourcesfor crop production by virtue of their small size, durability, longoperating lifetime, wavelength specificity, relatively cool emittingsurfaces and linear photon output with electrical input current. Work atNASA's Kennedy Space Center has focused on the proportion of blue lightrequired for normal plant growth as well as the optimum wavelength ofred and the red/far-red ratio. The addition of green wavelengths forimproved plant growth has also been addressed. [“Plant Productivity inResponse to LED Lighting”, G. Massa et al, HortScience, December 2008,vol. 43, no. 7, 1951-1956]

However, the inability of such prior art lighting systems to providesubstantially equal light distribution limits implementation thereof foran indoor plant growth unit of large vertical dimensions.

Another drawback of prior art systems for cultivating plants is thesafety of workers, when pest control is needed, in which case the entirecultivating space is sprayed by pesticide. This implies using a greateramount of pesticide. However, some pesticides may cause cancer and otherhealth problems, as well as harming the environment.

It is an object of the present invention to provide an indoor soillesscultivating system for the sustainable crop production of a safe andvaried food supply.

It is an additional object of the present invention to provide an indoorsoilless cultivating system with a lighting system that maintains asubstantially equal light distribution to facilitate photosynthesis atan indoor plant growth unit of relatively large vertical dimensions.

It is an additional object of the present invention to provide an indoorsoilless cultivating system by which the operating and capital costs oflight sources used to simulate the light cycles required byphotoperiodic flowering plants are significantly reduced relative tothose of the prior art.

It is yet an additional object of the present invention to provide anindoor soilless cultivating system by which the operating and capitalcosts of cooling systems for removing the heat generated by lightsources that simulate the cyclical nature of natural sunlight aresignificantly reduced relative to those of the prior art.

It is yet another object of the present invention to provide an indoorsoilless cultivating system which saves a substantial amount of therequired pesticide to be sprayed, to thereby reduce the exposure ofworkers and the environment to harmful effects.

Other objects and advantages of the invention will become apparent asthe description proceeds.

SUMMARY OF THE INVENTION

The present invention provides an indoor soilless plant cultivatingsystem, comprising a plurality of stationary light posts, each of whichadapted to illuminate a predetermined sector of an indoor facility inaccordance with a predetermined illumination signature; a plurality ofplant growth towers that are rotatable about a substantially verticalaxis in accordance with a predetermined timing sequence so as to beexposable to the light generated at any given time by one or more of thelight posts and that are arranged by at least one module defining amodule darkened interior region within which plants beinginstantaneously positioned receive a sensation of nighttime; andirrigation means for supplying the plants being cultivated in each ofsaid towers with a nutrient-rich solution.

The system further comprises a drive unit for cyclically rotating eachof the towers so as to be sequentially exposed to morning lightconditions, noon light conditions, afternoon light conditions andnighttime conditions in accordance with the illumination signatureemitted by the light posts of the at least one module. The drive unitmay be configured to cause a complete tower rotation once every 24-hourperiod.

Each of the towers is preferably configured with a plurality of mountingelements by each of which a corresponding plant is mountable at adifferent tower peripheral portion and is urged to grow outwardly fromsaid peripheral portion, groups of said mounting elements being definedat different height levels of the tower.

Leaves of all of the plants being grown on one of the towers are exposedto a substantially uniform distribution of light emitted from lightelements mounted on an adjacent one of the light posts for a givenemulated time period despite a height differential between the plants.

To achieve the substantially uniform distribution of light, the lightelements may be sufficiently small such that they have a density of noless than 40 light elements within a light post height of 50 cm and aremounted on each of the light posts in such a way that only one lightelement is mounted at any given height. A segment of the light elementshas a predetermined number and sequence of light elements arranged suchthat constituent beams emitted from the light elements of said segmentare mixed within a conical distribution angle to provide aphotosynthetic photon flux density at the tower peripheral portion uponwhich the mixed beam impinges that stimulates photosynthesis for a givenplant being grown. Thus the photosynthetic photon flux density atanother tower peripheral portion being illuminated at the given emulatedtime period is substantially equal.

The predetermined number and sequence of light elements are preferablyrepeated along the height of the light post for all other segments.

In one aspect, each of the light elements is provided with a directionallens configured to produce a light emitting angle whose angularboundaries are incident on the tower periphery, causing propagation ofthe emitted light to an internal region of the module between twoadjacent towers to be blocked as a result of its incidence on the towerperiphery, to thereby ensure that said internal region will be darkenedto a radiation level less than a predetermined photosynthetically activeradiation level for the plant being cultivated.

The plant cultivating system provides at least the following advantages:

-   -   A modular scalable system that is simple to ship, build and        maintain.    -   The system can be deployed in any existing building with any        geometrical shape regardless of its original purpose.    -   Dynamic allocation of the number of towers inside the same        facility, or on different floors of the same facility, for        different crops depending on seasonal demand or opportunities.    -   The facility is isolated from outdoor conditions to support        plant cultivation every hour and every day of the year        regardless of the outdoor weather conditions and climate.    -   Substantial shortening of the growth cycle of each plant, for        extremely fast growth of high quality products.    -   The number of plants able to be grown in the system for a given        area is 7 times greater as compared to traditional hydroponic        growth.    -   Operation of the system approaches an optimum point in combining        usage of light, air, water which are the most critical elements        conducive to plant growth.    -   The plants being grown are not subject to damage due to extreme        meteorological conditions and natural disasters.    -   Crops have maximum nutritional values, superior taste and        freshness.    -   Reduced refrigerated transportation time and cost.    -   As the cultivating system is soilless, 95% less water is        required to grow the crops than prior art systems.    -   No greenhouse gas emissions.    -   Easy and relatively inexpensive closed perimeter security and        surveillance systems, preventing agricultural theft losses that        are on the rise worldwide.    -   No soil pollutants.    -   Solution of land shortage problem.    -   Airflow system by which plant-released carbon dioxide is        transported to a daytime region for an improved photosynthesis        process.    -   Artificial pollination.

The present invention is also directed to an indoor plant cultivatingsystem, comprising a plant growth apparatus on which one or more plantsare mountable;

-   -   a stationary light post adapted to illuminate said one or more        plants in accordance with a predetermined illumination        signature; and irrigation means for supplying said one or more        plants with a nutrient-rich solution, wherein each of one or        more segments of light elements mounted on said light post has a        predetermined number and sequence of light elements arranged        such that constituent beams emitted from the light elements of        said segment are mixed within a conical distribution angle to        provide a photosynthetic photon flux density at a peripheral        portion of said plant growth apparatus upon which the mixed beam        impinges that stimulates photosynthesis for said one or more        plants being grown.

The present invention is also directed to an artificial pollinationsystem, comprising a post on which are mounted an air discharge nozzle;a plant growth apparatus on which one or more pollen bearing plants aremountable; a sensor for detecting an instantaneous position of said oneor more plants; an air receiver tank for storage of compressed air; aconduit extending from said air tank and in fluid communication withsaid nozzle; a control valve operatively connected with said conduit;and a controller in data communication with said sensor and said controlvalve, wherein said controller is operable to command opening of saidcontrol valve for a predetermined time, when a signal transmitted bysaid sensor is indicative that at least one of said plants is in pollenreleasable proximity to said nozzle, so that a pulsed supply of thecompressed air at a sufficiently high pressure to induce release ofpollen from its anther and airborne transport of said released pollen toa carpel of the same or of an adjacent plant will be directed to saidplant in pollen releasable proximity to said nozzle.

The present invention is also directed to an adaptive apparatus for usein conjunction with an indoor soilless plant cultivating system,comprising a plant growth tower configured with a drive unit that isrotatable about a substantially vertical axis by a complete towerrotation once every 24-hour period; a plurality of stationary andcircumferentially spaced light posts on each of which are mounted aplurality of vertically spaced light elements, light emitted by saidplurality of light posts impinging on a periphery of said tower todefine an illuminated peripheral region that is illuminated inaccordance with a predetermined plant-specific illumination signatureand a non-illuminated region associated with said tower periphery thatis unimpinged by said emitted light; one or more stationary guiding rodsconnected to a housing element of said tower, to which said plurality oflight posts are mounted and by which a circumferential spacing betweentwo of said light posts is adjustable; and irrigation means forsupplying the plants being cultivated in said tower with a nutrient-richsolution, wherein said tower is rotatable about the substantiallyvertical axis so as to be sequentially exposed to morning lightconditions, noon light conditions, afternoon light conditions andnighttime conditions.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a plan view of a plant cultivating system, according to oneembodiment of the present invention;

FIG. 2 is a plan view of a plant cultivating system, according toanother embodiment of the invention;

FIGS. 3A and 3B are a schematic side view of two light posts,respectively, showing the relative arrangement of the light elementsmounted thereon;

FIG. 3C is a schematic illustration of the conical distribution angle oflight that is emitted from a light element segment of a light post andthat impinges upon a peripheral tower portion;

FIG. 4 is a schematic illustration in elevation view of one embodimentof irrigation means for irrigating plants being hydroponicallycultivated;

FIG. 5 is a schematic illustration in elevation view of one embodimentof irrigation means for irrigating plants being aeroponicallycultivated;

FIGS. 6A and 6B are schematic illustrations in elevation view of anotherembodiment of irrigation means for irrigating plants being aeroponicallycultivated;

FIG. 7 is a front view from within the interior of a portion of an outerwall of a tower used in conjunction with the irrigation means of FIG. 1;

FIG. 8 is a schematic illustration of a recycling system for efficientlyutilizing the irrigation fluid used in conjunction with the plantcultivating system;

FIG. 9 is a schematic illustration in side view of a temperature of aclosed-loop liquid circulation system air to control the temperature ofair in the vicinity of a tower;

FIG. 10 is a schematic illustration of an air circulation arrangementused in conjunction with the plant cultivating system for facilitatingan increase in plant growth;

FIG. 11 is a schematic illustration of an artificial pollination systemused in conjunction with the plant cultivating system;

FIG. 12 is a perspective view from the side of structural elements foruse in conjunction with a module of towers;

FIG. 13 is a perspective view from the top of the structural elements ofFIG. 12 , showing an upper frame and a centrally positioned ceiling fan;

FIG. 14 is an enlarged perspective view from the side of the upper frameof FIG. 13 , showing one embodiment of a drive unit for rotating atower;

FIG. 15 is an enlarged perspective view from the side of a tower wall ofFIG. 13 , showing a removable plant supporter;

FIG. 16 is a perspective view of a multidirectional spraying column;

FIG. 17 is a plan view of a module of towers, showing the relativeposition of the multidirectional spraying column of FIG. 16 ;

FIG. 18 is a schematic illustration of a control system used inconjunction with the plant cultivating system for modulating the lightenergy directed to the plants;

FIG. 19 is a schematic plan view of another embodiment of a module oftowers;

FIG. 20 is a perspective view of one of the towers of the module of FIG.19 and of two light post mounted guide rods to which it is connected;

FIG. 21 is an enlarged side view of a portion of the tower of FIG. 20 ,showing in perspective view two plant-received receptacles renderedtransparent that are engaged with the tower;

FIG. 22 is a side view of one of the receptacles of FIG. 21 whenseparated from the tower;

FIG. 23 is a cross sectional view of one of the receptacles of FIG. 21when engaged with the tower;

FIG. 24 is a method for developing a bud aeroponically orhydroponically;

FIG. 25 is a cross sectional view of a sponge that is usable inconjunction with the receptacle of FIG. 22 ; and

FIG. 26 is a schematic illustration of an embodiment of an airflowsystem.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is an energy efficient, indoor soilless plantcultivating system which employs a plurality of stationary light posts,each of which illuminates a predetermined sector of an indoor facilityin accordance with a predetermined illumination signature. The plants tobe cultivated are mounted on a plant growth unit provided withirrigation means (hereinafter “tower”) of a large vertical dimensionsimilar to that of each light post, for efficiently utilizing the innerdimensions of the facility, which may be an abandoned building in anurban setting or a building in an industrial park dedicated to be usedby the cultivating system. The system operates in conjunction with amodule that includes a predetermined number of towers, such that eachtower of a module is rotated by a drive unit about a vertical axis inaccordance with a predetermined timing sequence so as to be exposable tothe light generated at any given time by one or more of the light posts.An interior region of the module is not exposed to the light generatedby any of the module related light posts, and the plants instantaneouslypositioned within the darkened interior region receive the sensation ofnighttime.

The indoor facility is preferably isolated from the outdoor conditions,including light, humidity and temperature conditions, present outwardlyfrom the facility. The plant cultivating system is able to emulateoptimal outdoor growing conditions that are different from theinstantaneous outdoor conditions, so that the leaves of all plantssubjected to a controlled environment will be exposed to a substantiallyuniform light distribution for the given emulated time period despite aheight differential between therebetween. Even though the plants areisolated from the outdoors, the production of fruit and seed crops ismade possible by virtue of an artificial pollination system.

FIG. 1 schematically illustrates a plant cultivating system 10 in planview, according to one embodiment of the present invention. Plantcultivating system 10 comprises a plurality of modules, and for purposesof brevity, one of the modules 5 will be described.

Module 5 includes four circular towers 2 a-d arranged in a symmetricalsquare-like configuration. Eight evenly spaced light posts 6 a-h aredeployed adjacent to the imaginary perimeter 7 of module 5, such thatfirst row light posts 6 a-c are positioned adjacent to adjoining servicepass 11 a, third row light posts 6 f-h are positioned adjacent toadjoining service pass 11 b which is opposite to service pass 11 a, andsecond row light posts 6 d-e are positioned at the two sides,respectively, of perimeter 7 according to the illustrated orientation,while being positioned at an intermediate region of module 5 andinterposed between a first row and third row light post.

Service passes 11 a and 11 b, to be used for accessing the towers formaintenance, plant treatment and harvesting purposes, may have a widthof 70 cm. Harvesting may be carried out with manual carts that areadvanceable along rails. The carts may have a hydrologic raisingcapability to permit comfortable access to an upper tower region. Foruse during extreme cold weather conditions, a rail may be configured asa series of interconnected round hollow pipes through which warm wateris flowable, to support heat dispersion as a part of the ambient controlsystem of the facility. These pipes may have a unique mechanicalprofile, for example funnel-shaped, to assist in uniformly spreading theheat.

The light element of each of the light posts may operate continually, toemit light with a same constant light intensity throughout a morningperiod, a noon period, an afternoon period and a nighttime period, inaccordance with a predetermined post-specific illumination signature,along a predetermined angular sector S, e.g. 60 degrees. A number andsequence of the light elements are selected to generate a plant-specificand sector-specific signature defining the predetermined illuminationsignature.

The setting of the predetermined angular sector may be obtained by meansof a directional lens 9 provided with each light element mounted on apost and by a selected spacing between a light element and acorresponding lens. Directional lens 9 is preferably a diverging lensthat produces a predetermined diverging light emitting angle withrespect to a vertical and horizontal plane. Each light element also hasa designed illumination range.

The position of each of light posts 6 a-h is carefully selected so that,together with the predetermined diverging light emitting angle of thelenses and the illumination range of the light elements, the emittedlight will be incident on the periphery of one or two towers.Consequently, the propagation of emitted light becomes blocked as aresult of its incidence on the tower periphery or on a vessel mounted onthe tower periphery within which a plant is being grown. A boundary of adarkened region D interposed between the two second row light posts 6 dand 6 e is traced by a plurality of points of incidence, at least onepoint of incidence being localized at the periphery of each tower 2 a-dof module 5 by the light emitted by one of light posts 6 a-h associatedwith module 5. The blockage of the emitted light ensures that darkenedregion D will be darkened to a radiation level less than a predeterminedphotosynthetically active radiation level for the plant beingcultivated.

In the exemplary deployment of the light posts, the illuminationsignature of posts 6 a, 6 c, 6 f and 6 h simulates the lightingconditions of noontime at a region N. The instantaneous illuminationsignature of posts 6 b, 6 d, 6 e and 6 g simulates the lightingconditions of morning at a region M, and afternoon or evening at aregion A, with respect to light intensity and/or wavelength. Darkenedinterior region D is located beyond the limited illumination range ofthe lighting elements mounted on each of light posts 6 a-h, andtherefore plants instantaneously positioned within darkened region Dreceive the sensation of nighttime. A distance between the towers at adarkened region D may be 80 cm for towers having a diameter of 60 cm.

Each of towers 2 a-d has mounting means 17 by which each correspondingplant 19 is retained on the periphery of a tower while being exposed tothe light posts. The various plants are arranged in layers, so thatplants 19 are found throughout the height and circumference of a tower,for maximum utilization of the volume within the facility. Plants 19 mayalso be arranged in an inclined disposition, so that will be urged togrow outwardly from the tower without interfering with an adjacentplant.

The plant cultivating system of the present invention is conducive tothe growth of many different types of crops, particularly high qualitycrops that are not necessarily indigenous to the surroundings of thegiven facility by virtue of the optimal environment in which they aregrown, including leafy vegetables such as lettuce, chicory, tomato,cucumber, chili, pepper and spinach, berries such as strawberries,cranberries, blueberries and raspberries, and herbs such as herbs forflavoring, food, medicine and cosmetics, for example medical cannabis.

The circular configuration of the towers promotes trellising of climbingplants such as cherry tomatoes and grave vines around the towerperiphery to advantageously minimize usage of the module surface area.Removable supporters 211 (FIG. 15 ) may be plugged into vacant holes 208around the tower periphery to support the weight of the crop if the loadon the tower is anticipated to be excessive.

Directional lens 9 may be configured to produce a light emitting anglewhose angular boundaries, when taking into account the given towerdiameter and the given distance from a light post to a tower, aretangential with, or are otherwise incident on, the periphery of thetower. The propagation of the emitted light to an internal region ofmodule 5 is blocked as a result of its incidence on the tower periphery,to thereby ensure that the internal region between two adjacent towerswill be darkened to a radiation level less than a predeterminedphotosynthetically active radiation level for the plant beingcultivated, for example darkness levels of up to 90% or more. Thedarkness level is also assisted by the ongoing growth of the leaves orbranches of the plants which help to block the penetration of light intothe inner region.

The rotation of each of towers 2 a-d by means of a central verticalshaft and a drive unit allows each plant 19 to be cyclically exposed tomorning light conditions, noon light conditions, afternoon lightconditions and nighttime conditions by completing a full rotation aboutits vertical axis once every 24-hour period, thus simulating a dailyday/night cycle. The drive unit may be an electric motor, or ahydraulically or pneumatically actuated drive unit.

It will be appreciated that a tower need not rotate at a constant rate.If a selected plant flourishes when exposed to certain light conditions,the relative dwelling time of the plant in those optimum lightingconditions may be increased.

FIG. 2 illustrates a module 25 comprising three rotatable towers 2 a-c,providing darkened interior region D, to which the mounted plants arecyclically exposed, as described above.

The definition of the darkened interior regions by the aforementionedmodule configurations advantageously contributes to the safety ofworkers and other bystanders by deploying a multidirectional sprayingcolumn 231 illustrated in FIGS. 16 and 17 within a darkened region D.

Multidirectional spraying column 231, which may have a rectilinear orcurvilinear configuration, has a plurality of nozzles 234 that protrudein different directions. When pesticide is delivered through conduit237, for example in response to a controlled duty cycle via anunderground conduit, to spraying column 231, a spray is issued from eachnozzle 234 and is directed at each of towers 2 a-d. The extendingdirection and the spray pattern of each nozzle 234 are carefullyselected to avoid pesticide wastage as a result of unnecessary sprayingin a region R between towers.

Since towers 2 a-d are continuously rotated, all plants will be exposedto the sprayed pesticide. However, workers are generally located withinservice passes 11 a-b (FIG. 1 ) which are outwardly separated from themodules, and will therefore not be exposed to the sprayed pesticide.This spraying arrangement will increase the safety of workers and willsignificantly reduce, or substantially eliminate harm, to theenvironment by minimizing discharge of harmful pesticide. Also, theamount of pesticide needed for effective pest control will besignificantly reduced.

Even though the plants are grown in a soilless environment and aretherefore not susceptible to damage by soil dwelling pests, neverthelessSmall plantings that were germinated outside the facility and werealready infected by pests or bacteria before being mounted in a tower,and therefore need to be treated with pesticide.

FIGS. 12-15 illustrate exemplary structural features for use with theplant cultivating system.

As shown in FIG. 12 , the vertical shaft of each of the four towers 2a-d of module 5 is rotatably mounted from above in a corresponding seator bearing provided in an upper square or rectangular frame 191 and frombelow in a corresponding seat or bearing provided in a bottom bar 197.Upper frame 191 may be embedded in a roof or ceiling portion 189, or maybe internally open and positioned below roof or ceiling portion 189.

The eight stationary light posts 6 a-h are attached to upper frame 191and are in fixed contact with the underlying ground surface, light posts6 a, 6 c, 6 f and 6 h extending downwardly from a corresponding cornerof the upper frame and the remaining light posts being connected to acorresponding cross member 194 extending outwardly from a central regionof an upper frame side element. Each of the light posts is thuspositioned at a relatively short and defined distance from the peripheryof a tower, for example a minimal distance between the light post andtower periphery of 30 cm, although this distance is generally reduceddue to the presence of the growing leaves. While the tower rotates, theactual distance from a plant to the light post varies. The four bottombars 197 extend inwardly from a bottom portion of each of the lightposts underlying a corresponding corner of upper frame 191 and areconnected together.

The central opening of upper frame 191 facilitates the positioning ofceiling fan 162 (FIG. 13 ), the purpose of which will be describedhereinafter. Ceiling fan 162 may be suspended by a hangar attached to anoverlying ceiling region, so as to be positioned within the centralopening, whether at, above or below the height of upper frame 191.Alternatively, the grille 164 of fan 162 may be connected to two or moreside elements 193 of upper frame 191.

Each tower 2 a-d may be configured with one or more access hatches 199that cover a corresponding opening formed in the periphery of a tower.The hatches 199 enable maintenance workers to access the hollow core ofa tower, in order to clean or repair the tower periphery and theirrigation elements, for example, or for harvesting purposes. The hollowcore also facilitates the growth of plants with large sized tubers andbulbs.

As shown in FIG. 13 , each tower may be configured with a polygonalperiphery that is substantially circular, such that each verticallyextending and planar wall 192 defines a wall of the polygon. A pluralityof vertically spaced planting holes 208 by which a plant is mounted onthe tower are formed within each wall 192. If a plant has a size whichis not compatible with the opening of a planting hole 208, a supporter211 shown in FIG. 15 , e.g. configured as an elbow made of molded rubberor plastic, may be removably inserted in one of the planting holes toassist in securely mounting a differently sized plant.

For example, a tower configured with a height of 240 cm and a diameterof 57 cm was formed with 11 planting holes 208 in each wall 192, wheneach planting hole was spaced by 20 cm center to center from an adjacentplanting hole on the same wall.

Walls 192 may be made of an opaque or black material for optimal lightabsorption. The inner surface of a wall 192 may be provided with grooveddrainage channels, e.g. vertically extending, by which irrigation fluidis directed towards the roots of the plants, to thereby maximize usagethereof.

One embodiment of the drive unit is shown in FIGS. 13 and 14 . Aserrated wheel 196 is fixed to the upper surface 197 of each of thetowers, so as to be coaxial therewith. The longitudinal axis of serratedwheel 196 is rotatably mounted at the corresponding junction 200 betweenupper frame side element 193 and cross member 194, to facilitaterotation of the tower.

A terminal end 201 of a substantially horizontally disposedreciprocating piston rod assembly 202, which may be hydraulically,pneumatically or electrically actuated, is connected, e.g. pivotallyconnected, to bracket 207 extending downwardly from side element 193.Piston rod assembly 202 has a bifurcated head 206 that is adapted toreceive within its interior a tooth 198 radially extending from theperiphery of serrated wheel 196, when the piston rod is extended, and toapply a force to a side edge of tooth 198, causing serrated wheel 196and the tower connected thereto to rotate about its vertically orientedlongitudinal axis for a discrete angle depending on the predeterminedstroke of the piston rod. The piston rod is then retracted, inanticipation of an additional rotation initiating operation.

In order to ensure substantially homogeneous distribution of the lightemitted by the elongated light posts onto vertically spaced plants,which may be spaced along a common tower by a large difference in heightof as much as 3 meters or more, the light elements are densely mountedon each light post, for example 50 light elements are mounted within adistance of 50 cm such that only one light element is mounted at anygiven height. A number and sequence of light elements may be pinpointedin order to generate a plant-specific light signature that will optimizeplant growth.

FIGS. 3A and 3B schematically illustrates an exemplary sequence of thelight elements, which are shown in exaggerated size for clarity and aremounted on light posts 6 a and 6 b for generating an illuminationsignature that emulates the lighting conditions of noontime and ofreduced light intensity conditions, respectively. The light elements,which are vertically spaced and vertically aligned, are preferably LEDelements, although other light elements are also in the scope of theinvention. Each light post is preferably tubular, to maximize heatdissipation from the continually operating light elements. If sodesired, the light elements may be operated according to a selected dutycycle or time sequence, in order to generate a desired waveform.

Light elements for emitting the following five colors are illustrated:blue (B) at a wavelength of 440-460 nm for use mainly during noonconditions, green (G) at a wavelength of 505-530 nm, red (R) at awavelength of 620-650 nm for use mainly during morning/afternoonconditions, deep red (DR) at a wavelength of 650-680 nm, and cool white(CW) at a color temperature, or the temperature of an ideal black-bodyradiator that radiates light of a comparable hue, of 5000° K. Thesecolors were selected as they constitute the basic spectral components ofsunlight needed by plants, although other colors are also in the scopeof the invention.

The sequence of the light elements is carefully selected so as togenerate a desired plant-specific light signature as a result of theinteraction of the light beams emitted from adjacent light elements andof the vertical wavelength distribution throughout the length of thelight post. The light signature generated by two adjacent light posts isalso able to interact.

A segment 31 of light elements 33 having a height J is shown in FIG. 3C.Segment 31 includes a predetermined number of vertically spaced lightelements 33, for example 30 elements. Each light element 33 of segment31 emits a corresponding beam that impinges upon a peripheral portion 27of tower 2, which is spaced by a distance K from light post 6. Withinthe conical distribution angle 36 of light that is emitted from segment31, being bounded by equal sides L to define an isosceles triangle incross section, the constituent beams emitted from each light element 33are mixed to provide a photosynthetic photon flux density (PPFD) atperipheral portion 27 that optimally stimulates photosynthesis for thegiven plant being grown. Likewise the PPFD at any other peripheralportion 27, or at any leaf of the plant being cultivated which isadapted to absorb the emitted light, included within conical angle 36 issubstantially equal. The light element sequence of segment 31 isrepeated along the height of light post 6. for all other segments, forexample segment 32 adjacent to segment 31. This light elementarrangement thus promotes substantially equal light distribution to allplants being grown throughout the height of tower 2.

Morning and afternoon lighting conditions may be emulated, for example,by generating the following percentage of relative light energycorresponding to spectral components of light emitted from a lightelement segment: (1) dark blue at a wavelength of approximately 450 nm,12%, (2) red at a wavelength of approximately 660 nm, 62%, (3) infraredat a wavelength of approximately 730 nm, 7%, and (4) white at a colortemperature of 4000° K, 19%. Plants are generally exposed to thesemorning and afternoon lighting conditions for two quarters of a 24-hourperiod.

Noon lighting conditions may be emulated, for example, by generating thefollowing percentage of relative light energy corresponding to spectralcomponents of light emitted from a light element segment: (1) dark blueat a wavelength of approximately 450 nm, 34%, (2) red at a wavelength ofapproximately 660 nm, 31%, (3) infrared at a wavelength of approximately730 nm, 7%, and (4) white at a color temperature of 4000° K, 28%. Plantsare generally exposed to these noon lighting conditions for one quarterof a 24-hour period.

The tubular configuration of the light posts may also be utilized toenable circulation through their interior of an irrigation fluid. Theirrigation fluid flowing through the sealed interior of a light postcools the continually operating light elements, and in turn becomesheated to plant growth inductive temperature of approximately 30° C. Theheated irrigation fluid in turn is directed to the plants, for fosteringtheir growth. The normally unexploited energy source of heat dissipatedfrom light sources is therefore utilized to improve the plants' growth.

FIG. 4 illustrates one embodiment of irrigation means 30 for wateringthe plants which are being hydroponically cultivated. Cold irrigationfluid 34 is injected into the interior 37 of light post 6 and isprogressively heated as it rises within the light post interior. Thewarm irrigation fluid 34 is discharged from the top of light postinterior via emitter 39 to reservoir 46 located at the top of tower 2,for example at a rate of 1 L/min.

Each plant 19 being cultivated is retained in a basket 41 that allowsthe roots to be exposed to the irrigation fluid. Basket 41 is turn ismounted in a corresponding inclined hollow holder 45, e.g. cylindrical,which is secured to, or integrally formed with, the vertical outer wall45 of tower 2, allowing each plant 19 to suitably grow while beingexposed to the light emitted from elements 9.

A corresponding conduit 49 extends downwardly, for example at anincline, from reservoir 46 to a holder 43, or from a first holder to asecond holder therebelow, to introduce the irrigation fluid to eachholder. As each holder 43 is disposed at an incline with respect tovertical wall 45, the accumulation 52 of the introduced irrigation fluidis collected at the bottom of the holder at a height suitable for theimmersion therein of the roots of plant 19 so as to supply nutrients tothe plant, and then overflows in cascaded fashion to the holdertherebelow. The spent overflow eventually flows to reservoir 54 at thebottom of tower 2. Each conduit 49 may be semicircular so as to simulateoxidation within the cascading irrigation fluid while being exposed tothe surrounding air.

The effluent from bottom reservoir 54 flows through standpipe 56 to asecondary catchment tank 58 and then to main catchment tank 59 bygravity, to which fresh water is added via inlet 61. A blend tank 63receives the discharge from main catchment tank 59. Additives, such asnitrogen, phosphorus, potassium, and other essential nutrients normallyfound in soil, are added, in optimum concentrations and in correctbalance, are added. An aeration pump 67 delivers the produced irrigationfluid 34 to the inlet of the light post interior 37.

A sound emitter 51, e.g. a loudspeaker, may be mounted on the outer wallof light post 6, for generating acoustical signals that may be conducivefor the plant growth.

Irrigation means 70 illustrated in FIG. 5 may be used for wateringplants 19 which are being aeroponically cultivated. Irrigation fluid isintroduced from blend tank 63 to pipe 72 formed within the interior ofvertical shaft 74 by which tower 2 rotates. The blending of theirrigation fluid is similar to that described in FIG. 4 . A plurality ofvertically spaced foggers 76 mounted on vertical shaft 74 and in fluidcommunication with pipe 72 eject a mist 79 directed to the roots 81 ofplants 19 for providing a plentifully supply of oxygen. Each plant 19being cultivated is retained in a basket 41 which is fitted within anaperture formed in vertical wall 45 of tower 2, and is mounted at anincline by means of a corresponding oblique brace 77, thereby allowingroots 81 to be exposed to the irrigation fluid.

An exemplary arrangement of apertures 89 formed in outer tower wall 45is shown in FIGS. 6A and 6B.

At the same time, rotation of shaft 74 according to a predeterminedtiming sequence causes plants 19 to be exposed to the light generated atany given time by one or more of light posts 6. The interior of eachlight post interior is cooled by injected cold water 84 that isprogressively heated as it rises. The heated water 84 is dischargedthrough top plate 83 of tower 2 and is collected at bottom reservoir 54.

FIG. 7 illustrates a configuration of an outer wall 95 of the plantgrowth tower by which water conservation is considerably increased.Outer wall 95 is formed with a plurality of narrow slots 91, each ofwhich is preferably recessed in order to receive liquid discharge from afogger that has impacted the outer wall and would normally flowdownwardly into the bottom reservoir of the tower without irrigating aplant. Each slot 91 extends for example from upper edge 92 of outer wall95 to the periphery of an aperture 89 into which a plant growing basketis fitted, thereby providing another source of irrigation in addition tothe fogger discharge. A slot 91 need not be straight as shown, butrather may be curved, or assume any other desired shape or disposition.

FIG. 8 schematically illustrates an open-loop recycling system 110 forefficiently utilizing the irrigation fluid. In system 110, the roots 81of plants 19 retained within the interior of tower are aeroponicallyirrigated by means of the irrigation fluid that is delivered by highpressure feed pump 115 through central vertical pipe 72 of tower 2 andto vertically spaced foggers 76, to produce a mist environment.

The irrigation fluid is fed to feed pump 115 from second mixing chamber121, into which is introduced the discharge of both first mixing chamber117 and ozone generator 126, the latter serving to inject an oxidizingagent in the form of O2 or O3 into irrigation fluid for the purpose ofdisinfecting waterborne organisms and thereby enriching the fluid. Infirst mixing chamber 117 are mixed fresh water flowing through valve106, e.g. a control valve, and the discharge of dosage pump 124, e.g. aperistaltic dosing pump, which delivers a predetermined amount ofnutrients, such as nitrogen, phosphorus, potassium, and acid, needed bythe type of crop being cultivated.

Controller 135 is in data communication with feed pump 115, dosage pump124, and ozone generator 126, in order to regulate the conductivity andpH of the irrigation solution and to deliver it to foggers 76 atpredetermined times. Ozone generator 126 is generally commanded tooperate shortly before the activation of feed pump 115, to ensuresuitable oxygenation of the irrigation fluid. Controller 135 may also bein data communication with air conditioning system 137 and localdehumidifier 139 for maintaining a predetermined air quality, includinga desired degree of humidity, in the vicinity of each tower 2.

The surplus irrigation fluid not consumed by the plant roots 81 iscollected in a reservoir 101 at the bottom of tower 2. A condensatepump, upon being commanded by controller 135 at a predetermined time,delivers the collected irrigation fluid via conduit 146 to used fluidstorage tank 142, which also receives condensate delivered fromdehumidifier 139 via conduit 147. A recirculation pump in datacommunication with controller 135 delivers the reused fluid to firstmixing chamber 117 via conduit 148 and valve 138, which may be a controlvalve commanded by controller 135.

In addition to air conditioning system 137 and dehumidifier 139 (FIG. 8), the temperature of air in the vicinity of each tower may becontrolled by means of the closed-loop liquid circulation system 155shown in FIG. 9 . Pump 151 delivers the cooling liquid upwardly throughthe interior of light post 6 to become progressively heated while thecontinually operating light elements mounted on the light post becomecooled. The heated irrigation fluid discharged from the top of lightpost interior is pressurized by pump 153, and consequently flows at asufficiently high rate through liquid-air heat exchanger, e.g. aradiator, to cause the surrounding air 159 to become heated. The heatdepleted liquid is then introduced to pump 151. The increase intemperature of the surrounding air 159 may be controlled by the flowrateof the circulating liquid.

FIG. 10 illustrates an air circulation arrangement that facilitates anincrease in plant growth. A ceiling fan 162 is installed so as to becentrally positioned within, and above, darkened interior region D ofmodule 5. Since plants 19 release carbon dioxide during respiration atnight, darkened interior region D is characterized by an increasedconcentration of carbon dioxide relative to other regions of the module.During operation of ceiling fan 162, the plant-released carbon dioxide,or air saturated with the plant-released carbon dioxide, is subjected tosuction by ceiling fan 162, and is accordingly caused to be transportedto outer noontime regions N of module 5, or alternatively to morning orafternoon regions. Plants 19 require a significant amount of carbondioxide in order to conduct photosynthesis. By being able to direct thenormally unexploited source of plant-released carbon dioxide to adaytime region, plants 19 are advantageously able to undergo anincreased rate of growth while producing a larger amount of sugars andcarbohydrates during the photosynthesis process as a result of absorbinga corresponding increased amount of carbon dioxide. Ceiling fan 162 maybe deactivated when it overlies a region that is instantaneouslyilluminated with daytime light conditions.

The photosynthesis process is accompanied by loss of water as a resultof evaporation from the stomates, or microscopic openings in the leavesof a plant through which incoming and outgoing gases such as carbondioxide and oxygen and water vapor are released. The transport ofplant-released carbon dioxide to a daytime region, resulting in a largerdegree of photosynthesis, thus contributes to an even greater rate ofwater evaporation, inducing the plant in response to absorb acorrespondingly increased amount of water through its roots to maintainan optimal water balance. The plant may also be induced to absorb anincreased amount of water through its roots by commanding dehumidifier139 (FIG. 8 ) to maintain a relatively low moisture level in the plantgrowing space surrounding a tower relative to the high moisture levelwithin the core of a tower.

The intake of water through the roots of a plant is a major drivingforce for the movement of minerals from the roots and the transport ofphotosynthesis derived sugars throughout the plant. The plants grow inan optimal soilless environment at a controlled temperature andhumidity, and consume a very small amount of water relative to theiroutdoor cultivated counterparts. As the roots do not have to expend theplant's energy to penetrate soil in quest for water and nutrients, theunused energy can be utilized by the plant's metabolic processes inother ways. For example, fruits tend to be sweeter, while leafyvegetables achieve a crispy leaf texture since the plant utilizes theunused energy to produce more minerals.

It will be appreciated that the plant-released carbon dioxide may alsobe transported through ducts, for example connected to upper frame 191(FIG. 13 ), to a daytime region.

The temperature of the transported carbon dioxide, as well as fresh air,if desired to be mixed therewith, may be controlled by air conditioningsystem 137 as commanded by controller 135.

In another embodiment, the apparatus of the present invention may beused in conjunction with artificial pollination system 170 shown in FIG.11 .

Light post 176 carries a plurality of vertically spaced air dischargenozzles 173 which receive a pulsed supply of compressed air in parallelfrom air receiver tank 177. Air receiver tank 177 for storage ofcompressed air in turn is in fluid communication with compressor 174,positioned at a region of low humidity and possibly positioned on thefloor of the facility. Compressor 174 is activated when the pressurewithin tank 177 is less than a predetermined low value, and isdeactivated when the pressure within tank 177 is greater than apredetermined high value. A conduit 172 external to light post 176extends from tank 177 and is in fluid communication with each nozzle173, and a control valve 179 may be operatively connected with conduit172, adjacent to the outlet port of tank 177. Each nozzle 173 may have adiverging outlet to direct the discharged compressed air in a conicalpattern, to ensure impingement of the compressed air onto the stamen ofplant 19, for example a strawberry plant, to induce the release ofpollen 182 from its anther and the airborne transport of pollen 182 tothe carpel of the same or of an adjacent plant.

Artificial pollination system 170 of course is capable of inducing therelease of pollen from its anther only when the pollen bearing plant isreliably positioned in close proximity to a nozzle 173 at substantiallythe same height. Repeated and reliable rotational displacement of tower2 about its longitudinal axis 184 may be made possible by a step motor187, which is adapted to rotate tower 2 in discrete predetermined stepincrements in response to a command pulse received by the drivercircuit. Alignment of a plant with a corresponding nozzle 173 may beachieved by knowing the angular displacement of each step, the diameterof the tower and the number of plants that are mounted around thecircumference of the tower.

The efficacy of artificial pollination system 170 may be enhanced by acontrolled change in the local humidity. Controller 135 is thereforeoperable to perform the five stage process of (1) commandingdehumidifier 139 to significantly reduce the local humidity in thevicinity of tower 2, for example to a level of 20% for strawberries, toreduce the adhesiveness of the pollen and to thereby support release ofthe pollen bearing anther from the stamen filament, (2) receivinginformation from the driver circuit of motor 187 as to when, or as tohow many steps are made, until a given plant 19 will be positioned inpollen releasable proximity to nozzle 173, (3) commanding opening ofcontrol valve 179 for a predetermined time so that the compressed airwill be directed to a given plant, (4) commanding dehumidifier 139 tosignificantly increase the local humidity in the vicinity of tower 2following the anther release, for example to a level of 50% forstrawberries, to ensure viability of the pollen and the adhesiveness ofthe stigma on which the pollen is to be deposited, and (5) closingcontrol valve 179 at the conclusion of the pollination cycle.

The duration of the control valve opening may be regulated by controller135 in response to the instantaneous air pressure within air receivertank 177, to ensure a sufficiently high air flowrate to induce therelease of pollen from its anther. For example, each nozzle 173 may bespaced 30 cm from the tower periphery, and the pressure of air whenbeing discharged from the nozzle is about 6 bar, regardless of thenumber of nozzles.

FIG. 18 illustrates another embodiment of the invention wherein thelight emitted to the plants is modulated.

Several studies conducted by Dr. T. C. Singh, head of the BotanyDepartment at Anamalia University, India and others confirmed that themusic affects plant growth. Plants feel the vibration of the generatedsound waves, and will speed the protoplasmic movement in the cells, tostimulate the manufacture of more nutrients that will give a strongerand better plant.

[http://hubpages.com/living/the-effect-of-music-on-plant-growth, updatedon Nov. 12, 2015, Oct. 3, 2016]

Control system 240 directs modulated light energy to the plants tostimulate an improvement in metabolic processes similarly to a plantreaction to modulated acoustic waves. The modulated light energy isgenerated by a digital signal processing (DSP) module 245 configuredwith a suitable transfer function, which may be housed in controller 135(FIG. 10 ) or in any other suitable hardware component. In response tothe input of an audio file 241 transmitted by player 242, DSP module 245transfers the audio signal to discrete frequency components, and thenthese frequency components are sequentially transferred to modulatedvoltage components and modulated light wavelength components to generatea corresponding light waveform. DSP module 245 also controls the lightintensity of the light waveform, depending on the daylight region towhich the plants are presently exposed, and filters the light waveform.The output light waveform is transmitted to the programmable powersupply 247 of the LEDs 249 mounted on a light post to generate thedesired modulated light beam 251.

In another embodiment, all planting holes formed in the tower walls areassigned a unique identifier which is stored in a system database. Thefollowing information related to each plant being grown is associatedwith the identifier and is also stored in the database: time ofplanting, growing protocol parameters, geographical location at anygiven time, and time of harvesting. The precise real-time geolocation ofevery plant with respect to a service passage facilitates the use ofrobotics for plant harvesting.

FIG. 19 illustrates another embodiment of a module 305 of a plantcultivation system. Module 305 includes four tubular rotatable towers302 a-d of annular cross section that are arranged in a symmetricalsquare-like configuration. The vertical shaft of each tower is rotatablymounted within an upper bearing housing 203 connected to the uppersquare frame 191 shown in FIG. 12 and to a lower bearing housingconnected to a corresponding bottom bar 197 that extends horizontallyfrom a support column 195 extending downwardly to the underlying groundor floor surface from a corresponding corner of frame 191 to a centralregion of convergence at which it is connected to the other bars 197.Each bottom bar 197 is raised above the underlying ground or floorsurface. In this amendment, light posts 6 a-h shown in FIG. 12 may bedispensed with. Alternatively, module 305 may be configured with anyother suitable arrangement of structural elements.

For each of the towers, five or any other suitable number ofcircumferentially spaced, stationary light posts 306 a-e are positionedradially outwardly by a uniform radial distance R from the correspondingtower periphery 309, by the guide rods shown in FIG. 20 or by othersuitable positioning means, to illuminate the plants being grown with aplant-specific and sector-specific light signature. The illustratedangular distance between the first light post 306 a and the last lightpost 306 e in the clockwise direction according to the illustratedorientation that defines an illuminated region 313, schematicallyillustrated as a shaded region between a light post and the towerperiphery 309, is approximately 200 degrees, or any other suitableplant-specific limited angular distance. A circumferentialnon-illuminated region 314 between the last light post 306 e and thefirst light post 306 a in the clockwise direction according to theillustrated orientation is devoid of any light posts and essentially isnot exposed to the light emitted by light posts 306 a-e.

It will be appreciated that a module may likewise include threerotatable towers, suitably configured structural elements, and aplurality of circumferentially spaced light towers defining a limitedangular distance.

The plant cultivation system associated with module 305 may beconfigured with one or more of the same features as described above,including for example an artificial pollination system, an airflowsystem by which plant-released carbon dioxide is transported to adaytime region, irrigation means and recycling system, air conditionerand dehumidification system and modulation means.

All vertically spaced light elements mounted on each of light posts 306a-e emit light at a constant intensity throughout a 24-hour period. Adirectional lens affixed to a corresponding light element which ispreferably a diverging lens produces a predetermined diverging lightemitting angle G, for example 80 degrees, with respect to a vertical andhorizontal plane to suitably illuminate a peripheral region of theadjacent rotating tower by a beam 308 that is substantially aligned withall other beams generated by other light elements of the same lightpost. As a result of the predetermined light emitting angle G, two beams308 each of which propagates from adjacent light towers converge at aconvergence zone 315 positioned radially outwardly from thecorresponding tower periphery 309 by a maximum radial distancesignificantly less than R, for example R/5.

Similar to module 5 of FIG. 1 , each of towers 302 a-d rotates about itslongitudinal axis once every 24-hour period, allowing the plants beinggrown thereon to be cyclically exposed to the light emitted by theassociated light posts. By carefully selecting the percentage anddistribution of light elements on a light post, the plants being grownon a given tower are able to be sequentially exposed to morning lightconditions, noon light conditions, afternoon light conditions andnighttime conditions to emulate natural growing conditions.

Although each of the light elements emit light at a constant intensity,the plants being grown are exposed to a varying light emission while atower is being rotated even when exposed to noon light conditions. Forexample, a peripheral tower region separated from light post 306 c byradial distance R is exposed to a light emission of approximately 600PAR, and is exposed to a light emission of approximately 400 PAR whenseparated from the convergence zone between light posts 306 c and 306 dby radial distance R/5. Photosynthetic Active Radiation (PAR), measuredby the amount of micro-moles of light per square meter per second, is anindication of light emission within the photosynthetic range of 400-700nm used by plants for photosynthesis. The average value of the varyinglight emission is sufficient for optimal growth of the plants.

Alternatively, the plurality of light posts, for example three lightposts 306 b-d, positioned between first light post 306 a and last lightpost 306 e, help to provide the varying noon light conditions during therotation of a tower. The varying noon light conditions may be a resultof the change in light conditions resulting from the convergence of abeam having morning light conditions and a beam having noon lightconditions.

As described above, the light elements, which are generally LED lightelements, mounted on each of light posts 306 a-e generally emit one ofthe five colors of blue, green, red, deep red, and cool white, which arethe basic spectral components of sunlight needed by plants. The actualpercentage of the light elements generating a specific color is selectedto provide an optimal photosynthetic photon flux density for the givenplant being grown insofar as the constituent beams emitted from eachlight element of a given light post are mixed, generally being a mix ofwhite light, red light having an approximate wavelength of 630 nm andblue light having an approximate wavelength of 450 nm, and may vary fordifferent light posts. For example, the predominant color emitted by thelight elements of first light post 306 a and last light post 306 e isred to achieve a color temperature of 3800° K emulating sunrise andsunset hours of the day, while the predominant color emitted by thelight elements of the other light posts of a given tower is blue toachieve a color temperature of 4500° K emulating noon light conditions.

The non-illuminated region 314 of each tower is adjacent to, and faces,the non-illuminated region of the other towers of module 305 bycorresponding different directions to define a module darkened interiorregion, or dark zone 316, bounded by all non-illuminated regions of themodule and by a narrow intervening interspace 318 between a pair ofnon-illuminated regions. Intervening interspace 318 has a width equal toat least the width of two light posts. As plants instantaneously facinga non-illuminated region 314 are substantially unexposed to the lightemitted by light posts 306 a-e, the ratio of light intensity atnon-illuminated region 314 to the light intensity at an illuminatedregion 313 being no more than 1:30, they are able to receive a sensationof nighttime and release carbon dioxide during respiration since thephotosynthesis process will be interrupted when the plants are exposedto such a low light intensity level.

The circumferential spacing between any two of light posts 306 a-e of atower 302 may be adjusted in conjunction with circumferentiallyextending upper guide rod 322 and lower guide rod 323 shown in FIG. 20 .Each of light posts 306 a-e on which are mounted a plurality ofvertically spaced light elements 33 is configured with upper aperture311 and lower aperture 312 through which upper guide rod 322 and lowerguide rod 323 are inserted, respectively. Upper aperture 311 and loweraperture 312 are formed in a portion of a light post that is devoid of alight element and penetrate both side walls of the light post, beingconfigured with same curvature as upper guide rod 322 and lower guiderod 323, respectively. By this arrangement, any of the light posts isable to be circumferentially displaced along guide rods 322 and 323 to aselected location in order to define a desired circumferential spacingCP between light posts or a desired angular distance of the illuminatedregion. Following the circumferential displacement, upper and lowerlocking members well known to those skilled in the art (not shown), suchas pivotally displaceable or spring loaded locking members, are deployedto secure the light post to guide rods 322 and 323, respectively, toprevent additional circumferential displacement.

The illustrated guide rods 322 and 323 are shown to be circular hoopsthat are substantially concentric with tower periphery 309, and arefixed in position by means of a plurality of radial braces 327, e.g.four, extending from the non-illuminated region of the hoop to a samebearing housing 203. The radial distance R by which the hoops are spacedfrom tower periphery 309 is sufficiently less than the distance betweenthe tower periphery and each support column 195 (FIG. 12 ) to preventinterference therewith. Each of circular guide rods 322 and 323 may bediscontinuous and configured with a first end 329 that has a slightlylarger diameter than the second end, allowing the second end to bereceived within, and secured by frictional or mechanical engagement to,the first end. A guide rod, which is flexible to a certain extent, isallowed to be introduced within an upper aperture 311 or lower aperture312 when the first end is separated from the second end.

Upper guide rod 322 is positioned between upper edge 317 of towerperiphery 309 and square frame 191 (FIG. 12 ). Lower guide rod 323 ispositioned between lower edge 319 of tower periphery 309 and theplurality of bottom bars 197. A plurality of leg elements 326 extenddownwardly to the underlying ground or floor surface from lower guiderod 323 by a sufficient length, e.g. 10 cm, to ensure that the lowerguide rod will be positioned between lower edge 319 of tower periphery309 and the plurality of bottom bars 197.

Alternatively, guide rods 322 and 323 may be arcuate with apredetermined angular length, having a radius of curvature that issubstantially concentric with tower periphery 309. The average angularlength of arcuate guide rods is 180 degrees to provide 12 hours ofdaylight and 12 hours of darkness. Two radial fixation braces 327aligned with a non-illuminated region of the tower may extend from to asame bearing housing 203 to a corresponding circumferential end of thearcuate guide rod. The radial distance by which guide rods 322 and 323are spaced from tower periphery 309 is sufficiently less than thedistance between the tower periphery and each support column 195 (FIG.12 ) extending below a corresponding corner of square frame 191 toprevent interference therewith. The light posts are able to beindividually circumferentially displaced along the arcuate guide rods322 and 323 to a selected location in order to define a desiredcircumferential spacing CP between light posts or a desired angulardistance of the illuminated region.

An exemplary plant to be grown in tower 302 is a medicinal herb or aplant with cosmetic uses that is grown on the eastern slopes of amountain during the winter months that have on the average 9 hours ofsunlight. To accommodate the relative short daytime, the arcuate guiderods have an angular length of only 135 degrees and are operativelyconnected to four light posts. Since the plants are normally exposed tosunshine of relatively low intensity with the exception of noontime,some of the light posts emit light of relatively low intensity.Accordingly, the number of light elements mounted on the first lightpost is equal to one-half a nominal number of light elements and thepredominant color emitted thereby is red. The number of light elementsmounted on the second light post is equal to one-half the nominal numberand the predominant color emitted thereby is blue. The number of lightelements mounted on the third light post is equal to the nominal numberand the predominant color emitted thereby is blue. The number of lightelements mounted on the fourth light post is equal to one-half thenominal number and the predominant color emitted thereby is blue. As theplants being grown are naturally unexposed to the sunset hours due tothe concealment caused by the mountain, a last light post emitting a redpredominant color is unnecessary. In a controlled experiment, the yieldof the plant grown in a module of towers 302 increased 30% relative tothe yield of the same plant grown in an indoor greenhouse.

Also shown in FIG. 20 are a plurality of vertically andcircumferentially spaced planting holes 338 formed within towerperiphery 309. Each group of planting holes may be vertically aligned,or any other suitable arrangement for the planting holes may beprovided. Each planting hole 338 constitutes a void region within whicha plant growing basket 41 (FIG. 5 ) or receptacle 341 (FIG. 21 ) is ableto be fitted.

A plant growing receptacle 341 shown in FIGS. 21-23 is adapted not onlyto be releasably secured to tower periphery 309, but also to hold adedicated sponge 354 for increasing the shelf life of a plant beingcultivated. A sponge 354, for example made of polymeric material, hasgood water retaining characteristics and is adapted to transfer theretained moisture to the roots of the plant after the receptacle isremoved from the tower. In addition to its good water retainingcharacteristics, sponge 354 is imparted with capillarity-inhibitingproperties. The capillarity-inhibiting properties may be achieved whenthe sponge material is impermeable and relatively hydrophobic and thepores of the sponge are relatively large to receive within each pore asignificant amount of water, although capillarity-inhibiting propertiesmay be achieved in other ways as well.

By virtue of its capillarity-inhibiting properties, sponge 354 isassured of not becomes overly wet to prevent onset of root rot withouthaving to control the surrounding temperature. Reducing moisture at theroots independently of temperature is of much importance sincetemperature control is needed to ensure that a given plant will be grownat its natural climate conditions.

Receptacle 341 is configured with an annular periphery 343 made ofrelatively thick elastic or resilient plastic material within which theplant being grown is held. Annular proximal end 344 has a largerdiameter than periphery 343 to assist in manipulation of the receptacle.The distal end 347 of receptacle 341 insertable within the towerinterior TI, which may be rounded, is formed with a plurality ofapertures 348 by which the roots of the plant being grown are exposed toirrigation fluid and through which the roots are able to extend whenincreasing in size. A peripheral groove 352 for use in engagingreceptacle 341 to tower periphery 309 is formed in periphery 343proximate to apertures 348. While the diameter of receptacle periphery343 is greater than the diameter of a planting hole, the resilientperiphery is able to be momentarily compressed until its distal end 347is inserted through the planting hole. Upon release of the compressingforce, the receptacle periphery once again expands and a portion of thevertical tower periphery 309 is received in groove 352 to ensure secureengagement of receptacle 341.

Angle α between proximal end 344 and groove 352 may be selected toinduce growth of the plant structure in a specific direction that isconducive for optimal growth of the plant being cultivated. A leafyvegetable such as lettuce may be set at a smaller angle α closer to thevertical plane than a fruit. This selected angle at which the plantextends outwardly from the plant periphery also assists in preventinginterference with adjacent plants.

A sponge 354 is retained between proximal end 344 and distal end 347. Asthe plant continuously grows by virtue of the exposure to the irrigationfluid and to the light emitted by the light posts, the roots penetratethe porous sponge 354 and increasingly grow within the tower interior.When it is desired to market the plant, and particularly the fruits,herbs or vegetables grown thereby, receptacle 341 is simply detachedfrom tower periphery 309 by a reverse process, and the roots are cutoutwardly from the receptacle or at apertures 348 while severing thereceptacle. Sponge 354 is removed from the receptacle together with theremaining plant structure. The plant is then marketed together with thesponge as the sponge prolongs the shelf life. The cut roots may beutilized for the extraction of oil.

The process of plant cultivation is made more efficient by employingreceptacle 341 as the same receptacle can be used for both a germinationstage and a cultivation stage.

FIG. 24 illustrates a method for developing a bud aeroponically orhydroponically. Prior to the germination stage, a tray, for example astainless steel tray, which is configured with an array of identicalopenings is provided in step 402. The previously described receptacle isinserted within each opening in step 404 until an edge of the openingsupports a peripheral region of the corresponding receptacle, usuallyadjacent the distal end. A receptacle is generally manually insertedwithin each opening, but an automated insertion operation such as bymeans of a robot is also within the scope of the invention. A spongepiece made of the water-retaining and capillarity-inhibiting sponge iscut, removed or otherwise formed in step 406 to outer dimensionssuitable for insertion within the receptacle interior and in step 408with a recess suitable for receiving a plant related structure.

An exemplary sponge piece 426 having a thickness that is sufficient tofill each receptacle interior is shown in FIG. 25 . Recess 428 isrecessed from the upper edge 423 of a central region of the sponge pieceand has a predefined depth, length and width that are suitable forretaining the plant related structure, such as a seed or a shoot. Asingle shallow recess 428 is formed in order to retain a seed. When ashoot that is larger than a seed is retained, the recess is deeper andmay be cross-shaped or assume any other shape. Sponge piece 426functions not only as mounting means within a receptacle, but also asmeans for transporting moisture to the plant related structure mountedthereby.

Returning back to FIG. 24 , the sponge piece is inserted within thereceptacle interior in step 410. The outer dimensions to which thesponge piece is cut are intended to exactly fit the dimensions ofcorresponding receptacles. Alternatively, the outer dimensions are cutto a diameter slightly greater than the diameter of the correspondingreceptacle, so that when the sponge piece is forced to be downwardlydisplaced, it will be compressed and securely received by the peripheralwall of the corresponding receptacle. Then the selected plant relatedstructure is suitably introduced within, and retained by, the recess instep 412.

During the germination stage, which is carried out until buds aredeveloped in the retained plant related structure, irrigation intendedto be directed to the above-ground portions, i.e. portions of the plantrelated structure that are normally located above-ground when the plantis grown in the ground, for example the epicotyl of a seed from whichthe entire shoot system develops, is provided aeroponically orhydroponically in step 414.

Effective germination is dependent upon a sufficiently high moisturecontent of approximately 25-50% and upon a reliable source of oxygen. Agerminating seed is liable to rot if kept in a waterlogged state due tothe lack of oxygen. The use of a water-retaining andcapillarity-inhibiting sponge is well suited for the promotion ofgermination as the sponge constantly remains moist and transmits themoisture to the plant related structure. The sponge achieves a constantmoisture level after absorbing the irrigation liquid, without absorbingan additional amount of irrigation liquid and becoming overly wet.

Once the seed germinates and the resulting seedlet or shoot developsroots and buds in conjunction with the moisture received from the spongein step 416, the same receptacle carrying the sponge and plant relatedstructure is repositioned and engaged with the periphery of a plantgrowth tower in step 418.

The roots grow in the direction of the irrigation liquid provided withinthe tower interior. After the plant sufficiently grows aeroponically,the roots are cut in step 420 and the plant together with the spongepiece is removed from the receptacle in step 422 and marketed.

Another embodiment of an airflow system 445 for plant-released carbondioxide is illustrated in FIG. 26 to facilitate an increase in plantgrowth. Airflow system 445 comprises a vertical air discharge tube 448that is positioned in the central dark zone 316 (FIG. 12 ) of a givenmodule. Tube 448 is configured with a plurality of vertically andcircumferentially spaced discharge openings 443 formed within itsperiphery. A blower 452 is positioned within the interior of tube 448,adjacent to its closed bottom end. The upper inlet 441 of tube 448 ispositioned in the vicinity of the discharge of conditioned air from airconditioner system 137.

During operation of air conditioner system 137 and blower 452,relatively cold conditioned air CA discharged from air conditionersystem 137 is forced into tube 448 via inlet 441. The pressurized air DAgenerated by blower 452 is discharged through each discharge opening 443into central dark zone 316 and cools the plants instantaneously exposedto the dark zone in emulation of night-time conditions. The pressurizeddischarged air DA combines with the carbon dioxide CD released from theplants during respiration to force the latter to flow through eachintervening interspace 318 between each pair of adjacent towers 302 a-dto a corresponding photosynthesis-suitable zone. Thus air saturated withthe plant-released carbon dioxide, which has been warmed to atemperature greater than conditioned air CA, is caused to be transportedto an illuminated region of the module for the benefit of the plantsthat require a significant amount of carbon dioxide in order to conductphotosynthesis.

It will be appreciated that airflow system 445 is also suitable to beimplemented in conjunction with module 5 of FIG. 1 , and may replace theairflow system illustrated in FIG. 10 .

While some embodiments of the invention have been described by way ofillustration, it will be apparent that the invention can be carried outwith many modifications, variations and adaptations, and with the use ofnumerous equivalents or alternative solutions that are within the scopeof persons skilled in the art, without exceeding the scope of theclaims.

1. Adaptive apparatus for use in conjunction with an indoor soillessplant cultivating system, comprising: a) a plant growth tower configuredwith a drive unit that is rotatable about a substantially vertical axisby a complete tower rotation once every 24-hour period; b) a pluralityof stationary and circumferentially spaced light posts on each of whichare mounted a plurality of vertically spaced light elements, lightemitted by said plurality of light posts impinging on a periphery ofsaid tower to define an illuminated peripheral region that isilluminated in accordance with a predetermined plant-specificillumination signature and a non-illuminated region associated with saidtower periphery that is unimpinged by said emitted light; c) one or morestationary guiding rods connected to a housing element of said tower, towhich said plurality of light posts are mounted and by which acircumferential spacing between two of said light posts is adjustable;and d) irrigation means for supplying the plants being cultivated insaid tower with a nutrient-rich solution, wherein said tower isrotatable about the substantially vertical axis so as to be sequentiallyexposed to morning light conditions, noon light conditions, afternoonlight conditions and nighttime conditions.
 2. The apparatus according toclaim 1, wherein the tower is configured with a plurality of mountingelements by each of which a corresponding plant is mountable at adifferent tower peripheral portion and is urged to grow outwardly fromsaid peripheral portion, groups of said mounting elements being definedat different height levels of the tower.
 3. The apparatus according toclaim 2, wherein leaves of all of the plants being grown on one of thetowers are exposed to a substantially uniform distribution of lightemitted from light elements mounted on an adjacent one of the lightposts for a given emulated time period despite a height differentialbetween the plants.
 4. The apparatus according to claim 3, wherein thelight elements are sufficiently small such that they have a density ofno less than 40 light elements within a light post height of 50 cm andare mounted on each of the light posts in such a way that only one lightelement is mounted at any given height.
 5. The apparatus according toclaim 4, wherein a segment of the light elements has a predeterminednumber and sequence of light elements arranged such that constituentbeams emitted from the light elements of said segment are mixed within aconical distribution angle to provide a photosynthetic photon fluxdensity at the tower peripheral portion upon which the mixed beamimpinges that stimulates photosynthesis for a given plant being grown.6. The apparatus according to claim 5, wherein the photosynthetic photonflux density at another tower peripheral portion being illuminated atthe given emulated time period is substantially equal.
 7. The apparatusaccording to claim 5, wherein the predetermined number and sequence oflight elements are repeated along the height of the light post for allother segments.
 8. The apparatus according to claim 1, furthercomprising a dosage pump for delivering a predetermined amount ofnutrients needed by the type of plant being cultivated, and a controllerin data communication with said dosage pump which is operable toregulate conductivity and pH of the irrigation solution deliverable tothe irrigation means at predetermined times.
 9. The apparatus accordingto claim 1, which is mounted in an indoor facility that is isolated fromoutdoor conditions present outwardly from the facility.
 10. Theapparatus according to claim 9, further comprising an artificialpollination system for facilitating production of fruit and seed cropswithin the indoor facility.
 11. The apparatus according to claim 10,wherein the artificial pollination system comprises a plurality ofvertically spaced air discharge nozzles carried by each of the lightposts, a pulsed supply of compressed air received in parallel by saidnozzles from an air receiver tank serving to induce release of pollenfrom an anther of plants being instantaneously positioned in proximityof said nozzles.
 12. The apparatus according to claim 11, wherein theartificial pollination system further comprises a conduit external tothe light post which extends from the air tank and is in fluidcommunication with each of the nozzles, and a control valve operativelyconnected with said conduit and in data communication with thecontroller by which pressure of the compressed air is regulated.
 13. Theapparatus according to claim 12, wherein the artificial pollinationsystem further comprises a unit for controlling local air humidity inthe vicinity of each tower of the module, the controller being operableto: a) command said unit to significantly reduce the local humidity to alevel that ensures sufficient reduction in adhesiveness of the pollenfor supporting pollen release; b) receive information from a data sourceassociated with the drive unit as to when a given plant will bepositioned in pollen releasable proximity to the nozzle; c) commandopening of the control valve for a predetermined time so that thecompressed air will be directed to said given plant; d) command saidunit to significantly increase the local humidity following the pollenrelease to ensure pollen viability; and e) close the control valve atthe conclusion of a pollination cycle.
 14. The apparatus according toclaim 13, wherein the unit is an air conditioner and a dehumidifier. 15.The apparatus according to claim 1, further comprising means fortransporting plant-released carbon dioxide from a dark zone to aphotosynthesis-suitable zone of the tower, to induce an increased rateof plant growth as a result of absorbing a corresponding increasedamount of carbon dioxide.
 16. The apparatus according to claim 1,further comprising an open-loop recycling system for reusing surplusirrigation fluid not consumed by plant roots.
 17. The apparatusaccording to claim 1, wherein the light elements mounted on each of thelight posts are in continual operation and are cooled by means of acooling liquid introduced through a light post interior.
 18. Theapparatus according to claim 17, wherein the cooling liquid is theirrigation fluid.
 19. The apparatus according to claim 1, wherein thelight elements mounted on each of the light posts are modulated tostimulate an improvement in plant metabolic processes.